<span *ngIf="likeNum==0">
    <img src="../../assets/images/good.png" style="width:5%" (click)="likeAdd()">
    <em>{{like}}</em>
</span>
<span *ngIf="likeNum!=0">
    <img src="../../assets/images/wrost.png" style="width:5%" (click)="hateAdd()">
</span>
